1. Field of the Invention
This invention relates to cosmetic emulsions of the oil-in-water (o/w) type which are pourable at ambient temperatures and which show high stability and improved flow behavior.
2. Statement of Related Art
The viscosity and rheological behavior of oil-in-water emulsions have a major bearing on their stability and performance properties. For example, it is known that the stability of emulsions increases with increasing viscosity. Accordingly, cosmetic creams often contain consistency-generating (thickening) components, such as fatty alcohols, fatty acid partial glycerides or waxes which contribute significantly to the stability of the emulsion. However, there are many emulsions in which a liquid or pourable consistency is required for reasons of practical application. A reduction in viscosity can be achieved by reduction of the inner phase or by replacement of the consistency-generating components by more liquid components. However, any reduction of the inner phase is generally undesirable in terms of practical application because it impairs the strength and the appearance of the emulsion, i.e. the emulsions become transparent and visually unattractive in appearance. Omission or reduction of the consistency-generating components is often accompanied by a loss of emulsion stability.
Emulsions containing cationic emulsifiers, in which fatty alcohols and fatty acid partial glycerides are present as consistency-generating components and which are commonly used as liquid hair aftertreatment preparations, have the problem that fatty alcohols make hardly any contribution towards a creamy, rich appearance of the emulsions and that fatty acid partial glycerides actually reduce the conditioning effect. In addition, emulsions of the type in question show a tendency toward rethickening, i.e. they are in danger of undergoing a considerable increase in consistency or of completely losing their pourability after prolonged storage.